Headboard



FIG. 1 is a left front perspective view of an headboard showing my new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a side view, the opposite side being a mirror image of the side shown; and,

The bottom, top, and rear views are not shown and form no part of the claimed design.

The broken lines are for environmental purposes only and form no part of the claimed design. 

The ornamental design for an headboard, as shown and described. 